Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C68/00—Preparation of esters of carbonic or haloformic acids
  • C07C68/06—Preparation of esters of carbonic or haloformic acids from organic carbonates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G64/00—Macromolecular compounds obtained by reactions forming a carbonic ester link in the main chain of the macromolecule
  • C08G64/20—General preparatory processes
  • C08G64/30—General preparatory processes using carbonates
  • C08G64/305—General preparatory processes using carbonates and alcohols

Definitions

• the present invention relates to an improved method for producing aliphatic oligocarbonate diols from non-vicinal diols by transesterification with Dimethyl carbonate (DMC) in a gas-liquid countercurrent apparatus and subsequent Separation of residues of methanol and traces of dimethyl carbonate in one gas bubble generating apparatus.
• DMC Dimethyl carbonate
• the catalyst dissolved in the finished oligocarbonate can either be separated or masked by adding complexing agents and in Oligocarbonate are left.
• the procedure according to the invention makes production particularly economical of aliphatic oligocarbonate diols starting from inexpensive dimethyl carbonate possible.
• Aliphatic oligocarbonates are important intermediates to the person skilled in the art, for example for the production of plastics, paints and adhesives, e.g. by Implementation with isocyanates has been known for a long time. In principle, you cannot vicinal diols by reaction with phosgene (DE-A 1 595 446), bis-chlorocarbonic acid esters (DE-A 857 948), diaryl carbonates (DE-A 1 915 908), dioxolanones (DE-A 2 523 352) or dialkyl carbonates (DE-A 2 555 805).
• phosgene DE-A 1 595 446
• bis-chlorocarbonic acid esters DE-A 857 948
• diaryl carbonates DE-A 1 915 908
• dioxolanones DE-A 2 523 352
• dialkyl carbonates DE-A 2 555 805).
• Diphenyl carbonate has a special one of the carbonate sources mentioned above Significance because of DPC aliphatic oligocarbonate diols of particularly high Quality can be generated (e.g. US-A 3 544 524, EP-A 292 772).
• DPC reacts quantitatively with aliphatic OH functions so that after removing the resulting phenol all terminal OH groups of the oligocarbonate mixture for reaction with isocyanate groups be available. Furthermore, only very low concentrations of soluble catalyst required so that it can remain in the product.
• EP-A 798 327 also describes a two-stage process accordingly, in which an oligocarbonate is first produced with an excess of DMC terminal OH groups are inaccessible as methoxy carbonate groups, and only in an additional step is after adding another diol and after receive a total reaction time of 36 hours the oligocarbonate diol.
• the invention accordingly relates to a method for producing aliphatic oligocarbonates with a degree of capping of the terminal OH groups by methoxycarbonyl groups less than 5%, preferably less than 1% by reaction of dimethyl carbonate with aliphatic diols with a degree of conversion of the used Dimethyl carbonates greater than 80%, preferably greater than 90%, particularly preferred greater than 95%, in particular greater than 98%, characterized in that the implementation of dimethyl carbonate and aliphatic diols accelerated by soluble Catalysts are carried out in a gas-liquid countercurrent apparatus, followed by oligomerization with elimination of methanol and traces of dimethyl carbonate The gas bubbles in the oligocarbonate are generated in an apparatus.
• gas-liquid countercurrent apparatus e.g. a Bubble tray column with 2 to 20 trays, possibly with larger liquid hold-up, as they are state of the art; Bubble column cascades with 2 to 8, preferred 2 to 8, preferably 2 to 4 bubble columns, with several bubble columns without internals to prevent backmixing by a column with internals can be replaced.
• a gas-liquid countercurrent apparatus a cascade of 2 to 6, preferably 2 to 3, kettles are used, the kettles preferably with gassing stirrers are equipped.
• the process according to the invention is carried out at temperatures in the countercurrent apparatus between 100 and 250 ° C, preferably between 150 and 200 ° C and for printing between 0.8 and 8, preferably between 1 and 4 bar.
• transesterification catalysts can be used as soluble catalysts, in particular the hydroxides of the alkali and alkaline earth metals and the metal alcoholates of aliphatic alcohols with 1-8 C atoms of metals the I., II., III. and IV. main group, the II. and IV. subgroup or from the Group of rare earths used in the Periodic Table of the Elements according to Mendeleev become.
• Sodium and potassium alcoholates or titanium and Zirconium alcoholates are used, with titanium and zirconium tetraalcoholates preferred is used for diols which contain ester functions.
• Preferred transesterification catalysts are: sodium methylate, potassium methylate, Sodium hydroxide, potassium hydroxide, titanium tetra isopropylate and zirconium tetra isopropylate.
• catalyst concentrations are given in Weight percent metal, based on the aliphatic diol used, between 0.001 and 1%, preferably between 0.005 and 0.5%, particularly preferably between 0.02 and 0.2%.
• a bubble column cascade can be used as the apparatus that generates gas bubbles in the oligocarbonate or a boiler cascade is preferably used with gassing stirrers.
• the glass bubble generating device can also be used in the gas / liquid countercurrent apparatus be integrated.
• the invention is Process, preferably as a semibatch process, carried out with a large bubble column or a large kettle, preferably with a gas stirrer, into which the dimethyl carbonate is dosed and in which the demethoxylation takes place, as well as with an attached bubble tray column, small boiler cascade or Bubble column cascade in which the countercurrent transesterification takes place, the volume of liquid the countercurrent system part between 0.5 to 50%, preferably between 1 and 25%, particularly preferably between 2 and 12% of the boiler volume of the cauldron.
• the process according to the invention also allows oligocarbonate diols of the formula (1) a carbon number from 30 to 300, preferably from 60 to 200, particularly preferred to produce from 100 to 150.
• Prefers are diols with ester functions, such as those obtained through the use of caprolactone and Hexamethylenediol obtained can be used. Mixtures of Caprolactone can be used with the diols mentioned, the resulting ones Form ester diols in situ.
• gas bubbles in the gas bubble generating apparatus are created by introducing inert Gases such as nitrogen, argon, methane, ethane, propane, butane, dimethyl ether, dry natural gas or dry hydrogen in the gas bubble generating apparatus generated, the leaving the oligocarbonate, methanol and dimethyl carbonate containing gas stream are partially fed to the oligocarbonate again for saturation can.
• inert Gases such as nitrogen, argon, methane, ethane, propane, butane, dimethyl ether, dry natural gas or dry hydrogen
• These gas bubbles can also by introducing inert low-boiling Liquids such as pentane, cyclopentane, hexane, cyclohexane, petroleum ether, diethyl ether or methyl tert-butyl ether are generated, the substances being liquid or gaseous can be initiated and the methanol leaving the oligocarbonate and dimethyl carbonate-containing gas stream partly to saturate the oligocarbonate again can be supplied.
• inert low-boiling Liquids such as pentane, cyclopentane, hexane, cyclohexane, petroleum ether, diethyl ether or methyl tert-butyl ether are generated, the substances being liquid or gaseous can be initiated and the methanol leaving the oligocarbonate and dimethyl carbonate-containing gas stream partly to saturate the oligocarbonate again can be supplied.
• the substances for generating gas bubbles are preferably by means of ring nozzles or Fumigation stirrers introduced into the oligocarbonate, with ring nozzles preferred can be used for bubble columns and gassing stirrers for stirred tanks.
• a technical system for the production of oligocarbonate diols can, for example, be set up as follows: A 10 m 3 boiler with an inlet pipe for DMC reaching to the bottom and a gassing stirrer can either be connected to a vacuum pump or to a 4 or 4 pump via a condenser with a collecting vessel for low boilers. tiered bubble column cascade with pressure control valve, subsequent condenser and collecting vessel for low boilers. The boiler and each of the bubble columns can be heated. Each bubble column has a liquid volume of 100 L. The bubble columns are connected in series in such a way that the gas flow from the boiler and the mixture of aliphatic diol and catalyst are conducted in countercurrent.
• the boiler can be operated with the bubble column cascade at up to 3 bar overpressure or with the vacuum system at up to 50 mbar absolute pressure.
• the gassing stirrer of the reaction vessel can be operated either with fresh gas or with gas from the boiler room or with mixtures of these gases.
• a semibatch production can be carried out as follows: boiler and bubble columns are under nitrogen and are heated to the reaction temperature Dosing of the diol-catalyst mixture is started. The mixture becomes the top bladder column supplied, from which it continues after its full filling to the next one and finally flows into the cauldron. When the kettle is full, that the fumigation stirrer is immersed in the liquid, the DMC dosing is started, the gassing stirrer is put into operation and the pressure control valve on the desired pressure set. The condensate leaving the reactor from methanol and a little DMC is examined for its composition and the Amount of DMC to be corrected by the amount not taken.
• the connection between The boiler and the bubble column cascade are closed and the vacuum pump is opened.
• the gassing stirrer is operated with boiler gas. If the distillation rate subsides, the vacuum is increased until a vacuum of 150 mbar is reached.
• the Gas supply for the gassing stirrer on an inert connection to be entered changed, e.g. Nitrogen. From time to time the contents of the kettle can be built into the remains Methanol are examined.
• the method according to the invention allows the production of high quality oligocarbonate diols from DMC with good space-time yields, high sales of the DMC and low degree of capping of the terminal OH groups.
• the oligocarbonates produced by the process according to the invention can e.g. for the production of plastics, fibers, adhesives or coatings be used. You can continue as a binder, binder component and / or reactive thinners in solvent-free or low-solvent polyurethane coatings be used. They are suitable as a building block for moisture-curing Coatings, as a building block and / or binder component in solvent-based or aqueous polyurethane coatings. You can continue as Building block used for free polyurethane prepolymers containing NCO groups are used as well as a building block in polyurethane dispersions.
• the oligocarbonate diols produced by the process according to the invention can also for the production of thermoplastics such as aliphatic and / or aromatic polycarbonates, thermoplastic polyurethanes, etc. are used.
• The% data for the compositions of the distillates obtained are always mol%, while% contents for compounds in the bottom phases and catalyst contents of the aliphatic diols are always% by weight.
• the apparatus consisted of a 20-tray oil-thermostatted bubble tray column with an inner diameter of 5 cm and a liquid hold-up of approx. 850 ml.
• the column had a thermostatted dephlegmator at the gas outlet and at the liquid outlet an oil-heated natural circulation evaporator with a Liquid content of approx. 70 ml.
• the column was thermostatted with a stream of heat transfer oil at 120 ° C.
• the dephlegmator was heated to 80 ° C and the circulation evaporator to 180 ° C Oil heated.
• the column was operated at ambient pressure.
• the top column bottom was 640 ml per hour a 120 ° C mixture of hexamethylene diol with 0.28% potassium hydroxide pumped in.
• a 120 ° C. was simultaneously established between the column and the circulation evaporator warm gas stream initiated from dimethyl carbonate. This gas flow was through Evaporation of 330 ml of dimethyl carbonate generated per hour.
• the column thus had a molar ratio of DMC to hexamethylene diol of 1 fed to 1.25.
• Example 1 The experiment from Example 1 was repeated with the difference that instead of potassium hydroxide 0.14% sodium hydroxide was included in the hexamethylene diol stream.
• Example 2 The experiment from Example 2 was repeated with the difference that the triple Amount of DMC and hexanediol-sodium hydroxide mixture in the column was driven.
• the test apparatus from Example 1 was heated to 140 ° C., the dephlegmator had a temperature of 80 ° C and the circulation evaporator one of 220 ° C.
• On the top column bottom were 645 ml of a 140 ° C warm equimolar Mixture of hexamethylene diol, neopentyl glycol and cyclohexane dimethanol pumped.
• the mixture contained 0.1% sodium hydroxide.
• a 140 ° C warm gas flow generated by an hourly evaporation of 205 ml DMC initiated.
• the molar ratio of diol to DMC was thus about 2.1 to 1.
• the evaporator was replaced by approximately 660 g of a colorless liquid substance per hour leave.
• Gas chromatographic analysis of this mixture showed that approx. 0.7 % unbound methanol, 0.04% dimethyl carbonate, 3.8% unreacted hexamethylene diol, 4.4% unreacted neopentyl glycol, 3.5% unreacted cyclohexane dimethanol and 3.6% neopentyl glycol carbonate were included.
• the apparatus consisted of a 5 L flat ground pot with blade stirrer, breakwaters, Inlet tube, a 10-plate oil-heated bubble tray column with dephlegmator and a total condenser for the gas leaving the column.
• the column had a fluid hold-up of approximately 170 ml.
• the metering was stopped after three hours.
• distillate A total of 1475 g of distillate were produced during this time, which is composed as follows: 99.2% methanol, 0.6% dimethyl carbonate and 0.2% hexamethylene diol.
• the bottom flask contained 4456 g of a colorless liquid containing 3.4% methanol, Contains 1.1% DMC and 4.2% unreacted hexamethylene diol.
• the degree of capping of the terminal OH groups is therefore less than 0.05%.
• a particularly sensitive gas chromatographic head-space method before and after saponification with aqueous KOH showed 40 ppm free and 32 ppm built-in methanol.
• the degree of capping of the terminal OH groups is therefore less than 0.05%.
• the apparatus consisted of a 5 L flat ground pot with blade stirrer, breakwaters, Inlet tube, a 10-plate oil-heated bubble tray column with dephlegmator and a total condenser for the gas leaving the column.
• the column had a fluid hold-up of approximately 170 ml.
• a total of about 880 g of distillate were obtained during this time, that from about 85% methanol and 15% dimethyl carbonate.
• the sump contains 1.93% methanol.
• Dimethyl carbonate, hexamethylene diol and caprolactone are undetectable.
• the resulting aliphatic oligocarbonate is pale yellow in color.
• Example 7 The apparatus as described in Example 7 was rebuilt so that the Column separated from the surface grinding pot by actuating a valve and instead A vacuum pump is connected via cold traps and the pressure is regulated can. The nitrogen flow was adjusted via a mass flow controller and kept constant.
• Fumigation over a 3 cm long glass frit showed a content of built-in methanol of 45 ppm after just 12 hours.
• Example 7 The apparatus as described in Example 7 was rebuilt so that the Column separated from the surface grinding pot by actuating a valve and instead A vacuum pump is connected via cold traps and the pressure is regulated can. The nitrogen flow was adjusted via a mass flow controller and kept constant.
• the flat grinding pot was equipped with a gassing stirrer with two exit points for the gassing of the boiler contents equipped.
• the gas entered into the liquid phase could either come from the boiler itself originate or be introduced as a defined gas flow from the outside.
• the gassing stirrer ran at approx. 850 revolutions per minute.
• test conditions were like until nitrogen stripping described in Examples 10 to 11, except that the gassing stirrer the gas phase of the boiler entered the liquid phase very efficiently.
• the amount of distillate dropped to approx. 700 g and consisted of approximately 95% methanol and 5% dimethyl carbonate.
• the sump contained 2.16% methanol. Dimethyl carbonate, hexamethylene diol and Caprolactone are undetectable.
• Nitrogen was introduced via the gassing stirrer, which was then from the gas space of the boiler was decoupled after only 6 hours with 2 NL continuously Nitrogen has an installed methanol content of 40 ppm per hour.

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• 1999
  • 1999-01-09 DE DE19900554A patent/DE19900554A1/de not_active Withdrawn
  • 1999-12-15 US US09/461,832 patent/US6156919A/en not_active Expired - Fee Related
  • 1999-12-27 EP EP99125968A patent/EP1018504B1/fr not_active Expired - Lifetime
  • 1999-12-27 DE DE59903015T patent/DE59903015D1/de not_active Expired - Fee Related
  • 1999-12-27 ES ES99125968T patent/ES2185288T3/es not_active Expired - Lifetime
  • 1999-12-27 AT AT99125968T patent/ATE225765T1/de not_active IP Right Cessation
• 2000
  • 2000-01-04 CA CA002293960A patent/CA2293960A1/fr not_active Abandoned
  • 2000-01-07 JP JP2000001676A patent/JP2000204062A/ja active Pending

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